In typical optical fiber based optical communication systems, an optoelectronic device having one or more components (i.e., light sources or light detectors) transmits optical signals to, or receives optical signals from, one or more optical fibers. The optical fibers are mounted in a fiber optic connector that positions the ends of the optical fibers in close proximity to the optoelectronic component. A lens is placed between the fibers and the components to focus light into or from the optical fibers. When transmitting, the optoelectronic device converts electrical signals into optical signals and directs the optical signals into the optical fibers. When receiving, the optoelectronic device receives the optical signals from the optical fibers and converts the optical signals into electrical signals.
To provide optimum transfer of an optical signal to or optimum reception of an optical signal from an optical fiber, the optoelectronic component must be precisely aligned in three dimensions relative to the lens, and the combination of the component and the lens must be precisely aligned in three dimensions relative to the end of the optical fiber. If the optical transmission path is not precisely aligned, the quality of the optical communication can be significantly degraded. The core of the optical fiber has cross-sectional dimensions on the order of a few microns to a few tens of microns, and the lens and the optoelectronic device elements have similar cross-sectional dimensions. Precisely aligning the optoelectronic device, the lens, and the core of the optical fiber can be difficult because of the small dimensions. In particular, cross talk between an array of closely arranged VCSELs is problematic, as is the loss of data due to inefficient coupling to the optical fiber.
Therefore, an important step in building fiber optic transmitting and receiving modules for optical communication systems is aligning the optoelectronic component having an array of emitting surfaces with the lens array for optimal light transmission to and from the optical fibers. This alignment is on the three linear axes and a rotational axis to properly focus the light and align the optical paths between the multiple emitting (or receiving) surfaces and the multiple optical fibers to maximize signal strength.
Accordingly, there is a long felt need for an efficient method of coupling a light source, particularly a closely arranged array of light sources, with an array of optical light transmission elements, such as an optical fiber bundle array (FBA), which minimizes cross talk and improves coupling efficiency.